Machine and method for paint-roller manufacturing with integrated final cutting online

ABSTRACT

A paint roller manufacturing system and method are described. In an embodiment, an inner strip of material and an outer strip of material are wound about a mandrel in offset relation. The inner strip of material and the outer strip of material each comprise material that results in a final paint roller which shrinks by less than 2.5 percent of the final paint roller axial length, or which has shrinkage that varies by less +/−0.1%, upon hardening and setting. An adhesive is applied to at least a portion of the outer strip as it is wound about the mandrel. A length of fabric is wound about at least the outer strip to form a paint roller tube, and compression is applied to the paint roller tube while advancing the paint roller tube in a direction parallel to the mandrel. A precision measuring or sensing device is used to control a cutting device causing the cutting device to cut the advancing paint roller tube into pre-selected lengths prior to the paint roller tube hardening and setting.

FIELD

The present invention relates in general to the field of paint rollermanufacturing, and in particular to a novel machine and process forcutting operations in the manufacture of paint rollers.

BACKGROUND

Paint roller manufacturing typically involves multiple stages. By thelate 1980s, and into the 1990s commercially viable methods ofmanufacturing thermoplastic paint rollers were developed. See, e.g.,U.S. Pat. Nos. 5,195,242, 5,572,790 having a common inventor herewith.These patents describe continuous processes of manufacturing paintroller sticks. Sticks are several times the length of a finished paintroller. Thermoplastic paint rollers used heat or molten plasticmaterials in the process of manufacturing paint roller sticks. Forexample, many processes used molten polypropylene or moltenpolypropylene compounds with melting points in excess of 300 degreesFahrenheit.

Sticks are typically 65 inches long when they come off a production line(e.g., as the end product of a continuous production line) at anelevated exterior temperature. For example, a stick may be cut from theoutput of a continuous processing line with an exterior temperaturesthat is greater than 90 degrees Fahrenheit, or greater than 100 degreesFahrenheit, or greater than 110 degrees Fahrenheit. Internal componentsof the sticks may remain much hotter than the exterior temperature whencut.

After manufacture, the sticks are allowed to cool, harden and set overtime. During the cooling, hardening and setting processes, the sticksshrink, often substantially, e.g., more than an inch, or more than 1.5inches. Indeed, it is likely that the principal reason for thehistorical selection of 65 inches as the industry standard stick lengthis the ability to cut seven 9-inch paint rollers (which is a verypopular size) therefrom, after shrinkage. After the sticks are hardenedand set, and thus have shrunk, they are cut down to final paint-rollerlengths. In an embodiment, a, typical paint roller length may be 3, 4,6, 7, 9, 12, 15, or 18 inches long. Other lengths (e.g., metric lengths)may be used as well. As an illustration, a 65-inch stick that hashardened and set may have shrunk by well over an inch, but it can stillbe cut into to seven 9-inch paint rollers. Other typical stick sizes maybe used (i.e., other than 65 inches) for making 9-inch or other rollersizes, however, all sticks are sized to allow for substantial shrinkageand result in waste in the cutting process.

Prior to the invention described herein it was well known to personsskilled in the art that cutting a paint roller stick into paint rollersof final length should not be done until all or substantially all of the(axial and radial) shrinkage has occurred. Thus, typically, finalcutting of paint rollers would not be performed until the stick hashardened and set. For example, final cutting may be performed when theexterior surface of the stick has a temperature of less than 90 degreesFahrenheit or less than 100 degrees Fahrenheit.

BRIEF DESCRIPTION OF THE DRAWINGS

Objects, features, and advantages of the invention will be apparent fromthe following description of preferred embodiments as illustrated in theaccompanying drawings, in which reference characters refer to the sameparts throughout the various views. The drawings are not necessarily toscale, emphasis instead being placed upon illustrating principles of theinvention.

FIG. 1 shows a top view illustrating a machine and two-strip process formanufacturing paint rollers in accordance with an embodiment whereinpaint rollers are manufactured and cut to final length in a singleprocess.

FIG. 2 shows a top view illustrating a machine and one-strip process formanufacturing paint rollers in accordance with an embodiment whereinpaint rollers are manufactured and cut to final length in a singleprocess.

FIG. 3 shows a paint roller tube traveling through a machine past aseries of notches into which one or more sensors and/or switches areinserted.

DETAILED DESCRIPTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The following description and drawings are illustrative andare not to be construed as limiting. Numerous specific details aredescribed to provide a thorough understanding. However, in certaininstances, well-known or conventional details are not described in orderto avoid obscuring the description. References to one or an embodimentin the present disclosure are not necessarily references to the sameembodiment, and such references mean at least one.

In a two-strip embodiment of the process, an inner strip of material andan outer strip of material are wound about a mandrel in offset relation,the inner strip of material and the outer strip of material eachcomprising polypropylene or a polypropylene compound includingpolypropylene and at least one filler.

In an embodiment, the materials used (e.g., the proportions ofpolypropylene to filler) are selected to result in a shrinkage (betweenthe cut length of paint roller and the final hardened-and-set length) ofless than 2.5%. In an embodiment, the materials used should be selectedto reduce roller-to-roller variation in shrinkage to withinmanufacturing tolerances, such as to less than one tenth of 1 percent(0.1%). In an embodiment, the materials comprise a combination ofcalcium carbonate and blend of polypropylene, with the calcium carbonateranging from 10-70% by weight. In an embodiment, the materials comprisea combination of calcium carbonate and blend of polypropylene, with thecalcium carbonate ranging from 50-66% by weight.

In an embodiment, the materials used are selected to result in ashrinkage of less than 0.6% or 0.05 inches for a 9″ paint roller. In anembodiment, the materials used should be selected to reduceroller-to-roller variation in shrinkage to within manufacturingtolerances, such as to less than 0.013% or 0.001 inches for a 9″ roller.In an embodiment, the materials used are selected to result in ashrinkage of less than 1.2% or 0.1 inches for a 9″ paint roller. In anembodiment, the materials used should be selected to reduceroller-to-roller variation in shrinkage to within manufacturingtolerances, such as to less than 0.026% or 0.002 inches for a 9″ roller.In an embodiment, the materials used are selected to result in ashrinkage of less than 2.4% or 0.2 inches for a 9″ paint roller. In anembodiment, the materials used should be selected to reduceroller-to-roller variation in shrinkage to within manufacturingtolerances, such as to less than 0.052%, or 0.004 inches, for a 9″roller. Applying the foregoing to an 18 inch paint roller, in anembodiment, the materials used should be selected to result in ashrinkage of less than 0.11 inches or less than 0.22 inches, or lessthan 0.33 inches. In an embodiment, the materials (e.g., proportions ofpolypropylene to filler) are selected to result in a final paint rollershrinkage which is repeatable. In an embodiment, the materials areselected to result in a final paint roller shrinkage which is repeatablewithin normal manufacturing tolerance (i.e., that the finished paintrollers manufacture with the materials harden and set to the finishedlength within manufacturing tolerance.)

Shrinkage also occurs radially, in addition to axially as discussedabove. In other words, there is some reduction in paint roller diameterdue to shrinkage. Rollers manufactured with a compound that includes afiller, as described herein, shrink less than traditionalpolypropylene-only rollers. Polypropylene-only rollers are typicallymade with an internal diameter of 1.52″, and shrink to a finishedinternal diameter of 1.485″, which represents a shrinkage of about 2.3%.Rollers manufactured with a compound that includes a filler aretypically made with an internal diameter of 1.5″, and they shrink to1.485″, which represents a shrinkage of about 1%. Mini rollers, whichtypically have a length of 4.5 inches and a diameter of 0.5 inch or ¾inch, or a length of 6.5 inches and a diameter of 0.5 inch or ¾ inch,are subject to similar shrinkage. Therefore, rollers of all sizes madewith such compounded material shrink less, typically more than 50% less,than paint rollers made solely from the more traditional polypropylenematerial.

In an embodiment of the present invention, an adhesive is applied to atleast a portion of the outer strip as it is wound about the mandrel, alength of fabric is wound about at least the outer strip to form acontinuous paint roller tube, and compression is applied to the paintroller tube. The paint roller tube may be cut into pre-specified lengthsinline with the manufacturing process prior to the paint roller tubehardening and setting. In an embodiment, a precision measuring and/orsensing device is used to control a cutting device so as to cut thepaint roller tube into pre-specified lengths prior to the paint rollertube hardening and setting. In an embodiment, a measuring and/or sensingdevice controls a cutting device which cuts the continuous paint rollertube into pre-specified lengths inline with the paint roller tubemanufacturing process prior to the paint roller tube hardening andsetting. The cut lengths of paint roller tubes are subsequently allowedto harden and set. In an embodiment, the hardened and set cut paintroller tube is the desired length of a paint roller. In an embodiment,the hardened and set cut paint roller tube is the desired length of apaint roller, within normal manufacturing variation.

FIG. 1 illustrates a two-strip embodiment of a paint rollermanufacturing system 101 for implementing the above process. The systemincludes a cover dispenser 122 that continuously dispenses a windablewidth of paint roller cover fabric 125, the paint roller cover fabrichaving a back side and an applicator side. The paint roller cover fabric125 may comprise a conventional cover fabric or a coated fabric that hasbeen coated offline or online, as is taught in U.S. Pat. No. 9,956,719which is incorporated by reference herein in its entirety and shares acommon inventor herewith.

A mandrel 121 is provided, and may be cooled by a mandrel cooler 133 soas to facilitate movement of strips around the mandrel in a helicalmanner without adhesion of the strips to the mandrel and with lowerresistance.

First and second strip dispensers 116, 118 are configured tocontinuously dispense first and second windable widths of strip material117, 119. A guide system (not shown) may be used to guide the first andsecond strip coming from the first and second strip dispensers such thatit is wound about the mandrel and to guide a paint roller cover fabricto be wound about the first and second strips 117, 119. In anembodiment, the paint roller fabric cover may be coated. In anembodiment, the paint roller fabric cover may be perforated. In anembodiment, the paint roller fabric cover may be coated and perforated.The second strip 119 and/or the first strip 117 may be a solid strip, aperforated strip or an embossed strip (e.g., having recessed dimples orother recessed features).

In an embodiment, the cover fabric 125 has been perforated in order toincrease adhesion of the fabric to the outer strip in a two-stripprocess, or to the sole strip in a single-strip process. Methods anddevices for perforating cover fabrics are taught, for example, in U.S.patent application Ser. No. 16/103,550 filed Aug. 14, 2018, which sharesa common inventor herewith and is incorporated herein by reference inits entirety. Paint roller fabric can either be perforated in the paintroller manufacturing process, or at any time prior to the fabric beingwound around the mandrel, such as when the fabric is manufactured. In anembodiment, perforating paint roller fabric may provide for greateradhesion and/or a reduction in shedding (i.e., the amount of fibers thatare dislodged during the paint roller manufacturing process or theprocess of using a finished paint roller).

In an embodiment, an applicator 115 is configured to apply adhesive(which may be glue, a polymer, or a compound polymer with or without afiller material) on substantially all of the outer side of the first andsecond windable strips 117, 119 upstream of a location where theconventional or coated paint roller cover fabric 125 is wound about thefirst and second strips. In an embodiment, the adhesive is in a moltenstate or a liquified state when applied. In an embodiment, the adhesiveis molten or liquified polypropylene. In an embodiment, the adhesive ismolten or liquified compound which includes polypropylene. In anembodiment, the adhesive is molten or liquified compound which includespolypropylene and calcium carbonate.

In an embodiment, a compressing and advancing device 129 is provided forapplying inward pressure normal to the mandrel on a conventional orcoated paint roller fabric cover 125 after it is wound about the firstand second strips 117, 119, and for advancing the first and secondwindable strips and the paint roller fabric cover along the mandrel 121.As discussed above, the paint roller fabric cover may be conventional,coated, perforated, or coated and perforated.

In an embodiment, the machine includes an extruder 103, which may beconfigured for extrusion of an adhesive material through a die 105. Inan embodiment, the material is molten when it is extruded through thedie 105 and the molten material is pushed through hose 111 to thestrip-coating adhesive applicator 115. The strip-coating applicator 115may comprise any device for applying liquid adhesive to a fabric,including a die head, sprayer, brush, extruder, or the like.

The inner strip 117 and outer strip 119 of material are helically woundabout the mandrel 121 in offset relation. In an embodiment, the offsetrelation is approximately 50%, that is, the center of one strip wraps ata location under or over (as the case may be) the middle of the otherstrip. In an embodiment, the offset relation is at least 5% to preventthe seams of the inner strip and the outer strip from aligning. A 5%offset relation refers to having the seam at least 5% of the width ofthe strip away from the edge of the strip. In an embodiment, the entireinner surface of the inner strip 117 contacts the mandrel 121. In anembodiment, no portion of the outer strip 119 contacts the mandrel 121.

In an embodiment, the inner strip 117 and the outer strip 119 comprise amaterial that, for a given roller length, will result in repeatableshrinkage due to hardening and setting. In an embodiment, the innerstrip 117 and the outer strip 119 comprise a material that, for a givenroller length, will result in repeatable shrinkage due to hardening andsetting, within a manufacturing tolerance.

In an embodiment, the outer surface of the inner strip 117 and the outersurface of the outer strip 119 are coated with adhesive by thestrip-coating applicator 115. In an embodiment (not shown), thestrip-coating applicator 115 comprises two separate strip-coatingapplicators, one to coat each of the two strips 117, 119. Thus, suchcoating of the outside of each of the two strips may be performed by thesame applicator or, in another embodiment, by two separate applicators.As shown in FIG. 1, coating of the strip or strips is performed by asingle applicator. In an embodiment, only the outer surface of the innerstrip 117 is coated with adhesive by the strip-coating applicator 115.In an embodiment, the strip-coating applicator 115 applies adhesive toeither the outer surface of the inner strip or the inner surface of theouter strip such that the adhesive ends out between the inner and outerstrips after it is applied. In an embodiment, the strip-coatingapplicator 115 applies adhesive to either the outer surface of the innerstrip or the inner surface of the outer strip such that the adhesiveends out between the inner and outer strips after it is applied, andliquid adhesive applied by an optional fabric coating applicator is notset when the outer strip 119 and the fabric cover 125 come together onthe mandrel. In an embodiment, the strip-coating applicator 115 appliesadhesive to either the outer surface of the outer strip or the innersurface of the fabric cover 125 such that the adhesive ends out betweenthe outer strip and fabric after it is applied. In an embodiment, aportion of the outer surface (rather than the entire outer surface) ofthe outer strip 119 (or the only strip in a single-strip embodiment) iscoated with adhesive. In an embodiment, the entire outer surface of theouter strip 119 is coated with adhesive. The strip-coating applicator115, in each case, may be configured to apply a contiguous ornon-contiguous coat of material to the strip. Examples of anon-contiguous coat include, without limitation, a mesh of material, orstripes of coating material. In addition, the strip-coating applicationmay be configured to apply additional material, such as a mesh materialin addition to a coating material. In an embodiment, a mesh material anda contiguous coat of material are applied by the strip coatingapplicator 115. In an embodiment, the mesh material is a resin. In anembodiment, the mesh material is an adhesive mesh. In an embodiment,only a portion of the outer surface of the inner strip 117 is coatedwith adhesive. In an embodiment, the entire outer surface of the innerstrip 117 is coated with adhesive.

In an embodiment, the strips and/or adhesive are made from or comprisepolypropylene. In an embodiment, the strips and/or adhesive comprise acompound of polypropylene and a filler. In an embodiment, the fillercomprises calcium carbonate. A variety of formulations for strips and/oradhesive may be found, e.g., in Applicant's U.S. patent application Ser.No. 14/789,723 filed Jul. 1, 2015 and the references cited therein, theentire disclosures of which are incorporated herein by reference. It isnot necessary to use strips of identical materials. It is similarly notnecessary to employ an adhesive of similar materials to one or both ofthe strips.

In an embodiment, the material used for both or either of the strips maycomprise, for example: (1) commonly-available polypropylene; (2) a blendof polypropylene, with an effective Melt Flow Rate (MFR) of 2-20 g/10min.; (3) a combination of calcium carbonate (CaCO3) and Polypropylene,with CaCO3 ranges used from 10-70% CaCO3; or (4) a combination ofcalcium carbonate (CaCO3) and a blend of polypropylenes, with CaCO3ranges used from 10-70% CaCO3.

In an embodiment, the material used for the adhesive may comprise, forexample: (1) commonly-available polypropylene; (2) a blend ofpolypropylene, with an effective Melt Flow Rate (MFR) of 20-180 g/10min.; (3) a combination of calcium carbonate (CaCO3) and Polypropylene,with CaCO3 ranges used from 10-70% CaCO3; or (4) a combination ofcalcium carbonate and blend of polypropylene (having a high MFR rangingfrom 700-1400 g/10 min), with CaCO3 ranges from 10-70% CaCO3 by weight,for an effective total MFR of 20-180 g/10 min. In an embodiment, theadhesive comprises a combination of calcium carbonate and blend ofpolypropylene, the combination having an effective MFR within the rangeof 20-180 g/10 min. In an embodiment, the adhesive comprises acombination of calcium carbonate and blend of polypropylene, thecombination having an effective MFR within the range of 80-170 g/10 min.In an embodiment, the adhesive comprises a combination of calciumcarbonate and blend of polypropylene, the combination having aneffective MFR within the range of 160-175 g/10 min.

Once the component parts (e.g., strips, adhesive, cover) are wound aboutthe mandrel 121, the in-process paint roller cover material tube 127 maybe driven by a motorized compressing and advancing device. In anembodiment, the in-process paint roller cover material tube 127 isdriven by a compressing and advancing device comprising a belt 129driven by a motorized roller 137. Operation of the motorized roller 137may be controlled by a process controller 138 in one-way or two-waycommunication with the motorized roller 137.

The formed paint roller cover material tube 127 is advanced along themandrel 121 by the belt 129 to a cutting device 131 that cuts the tubeinto lengths. The cutting device 131 may be, e.g., a rotary cutter, aflyaway saw, a traveling saw, a stationary cutter, or other suitablecutter or chopper. In an embodiment, the cutting device is under thecontrol of the process controller 138.

The process controller receives a signal from a precision measuringand/or sensing device 133, the signal indicating that the tube 127 hasadvanced to a particular point either along or after the mandrel 121.The precision measuring and/or sensing device 133 may be, e.g., amechanical, optical, electromagnetic, Hall effect, piezoelectric, ormagnetic sensor capable of measuring a desired length of the tube 127,or detecting or determining a location of the tube 127 with sufficientprecision, accuracy, and speed to allow the cutting device 131 to cutthe tube 127 such that once set, the cut lengths result in tubes in adesired length (e.g., a paint roller length) within a manufacturingtolerance. In an embodiment, such tolerance is less than 0.001 inchesper final paint roller length. In an embodiment, such tolerance is lessthan +/−0.002 inches. In an embodiment, such tolerance is +/−0.004inches. In an embodiment, such tolerance comprises shrinkage of lessthan 0.05 inches per final paint roller length. In an embodiment, suchtolerance comprises shrinkage of less than 0.10 inches per final paintroller length. In an embodiment, such tolerance comprises shrinkage ofless than 0.20 inches per final paint roller length. In an embodiment,such tolerance comprises shrinkage which varies by less than 0.004inches per final paint roller length. In an embodiment, such tolerancecomprises shrinkage which varies by less than 0.8 percent of the finalpaint roller length.

The precision measuring and/or sensing device 133 is illustrativelyshown in FIG. 1 downstream from the cutting device 131, however, theprecision measuring and/or sensing device 133 may be located atvirtually any part of the machine where there is movement proportionalto the manufacturing process. In an embodiment, the precision measuringand/or sensing device 133 is located at a part of the machine past whichthe tube 127 is moving. In an embodiment, the precision measuring and/orsensing device 133 is located at a part of the machine past which one ormore of the strips 117, 119 or cover 125 are moving. In an embodiment,the precision measuring and/or sensing device comprises a shaft encoderon the shaft of motorized roller 137. In an embodiment, the precisionmeasuring and/or sensing device comprises a shaft encoder on the shaftof one or more of rollers 116, 118, and 122. In an embodiment, theprecision measuring and/or sensing device comprises a wheel in contactwith either strips 117, 119, or cover 125, or any combination of thosecomponents. In an embodiment, the precision measuring and/or sensingdevice comprises a wheel in contact with the tube 127.

The process controller 138 is in communication with a selectioninterface 141, which may comprise hard buttons and/or a touch interfacewith soft buttons, that allow selection of final paint roller length.The selection interface 141 is in direct or indirect communication withthe cutting device 131 and/or the precision measuring device 133, and isconfigured to allow an operator to select the final paint roller lengthfrom one of a plurality of preset lengths to another of the plurality ofpreset lengths. Examples of such preset lengths include, e.g., threeinches, four inches, four and a half inches, six inches, six and a halfinches, seven inches, nine inches, twelve inches, fifteen inches, andeighteen inches. Based on such selection, and the signal from theprecision measuring device 133, the process controller 138 causes thecutting device 131 to be actuated with a specific timing that results inthe length of the final paint rollers 143 to be at or near a lengthselected using the selection interface 141. The functions of the processcontroller may be incorporated in whole or in part in other sensing,detecting, or computational components already in use elsewhere in theprocess.

Once rollers have been cut via the above-described inline cuttingprocess, they can be conveyed via a conveyor 145 to a finishing machine147 where they are finished. In an embodiment, finishing includesbeveling the edges of the final roller, trimming excess fabric, andremoving any detritus/debris. Finishing may include any other processthat a manufacturer requires before rollers are placed into packaging,and may include placement into packaging. In an embodiment, conveyor 145comprises a conveyor belt with short walls on either side.

The rollers can then be loaded into a loading mechanism such as amagazine. The process may further utilize an apparatus that evenlydistributes the rollers to a number of downstream finishing machines,based on various methods used to sense the current capacity/queue ateach of the machines. Various methods can be utilized for assessing how“busy” a finishing machine is. Such methods include, e.g., receiving andprocessing signals from electromechanical sensors, optical sensors, oroperator input.

In an embodiment, the finishing machine 147 includes a queuing stationand an indexing device. Once a roller has been deposited at the queuingstation of the finishing machine, the finishing process can begin. Theindexing device is used to finish rollers using functions performed ateach of a plurality of different stations selected per the particularmanufacturer's finishing requirements.

There are two main types of indexing machines, single-turntable machinesand dual-turntable machines. Single-turntable indexing machinestypically utilize a single rotary turntable that turns a roller througha plurality of stations. For example, a six-station machine would load,spin, buff, bevel, spin, and unload a roller. Spinning is used to removeexcess particles from fibers. One of the main issues with asingle-turntable process is that it typically is unable to easilyprocess a roller on both ends (i.e., the end of the roller that isclosest to the indexing turntable is hard to reach). A dual-turntableindexing machine, on the other hand, allows rollers to be finished atboth ends, using two sets of turntables. One example of a machine ofthis type uses two eight-station turntables that would each load, buff,bevel, shear, clean ends, spin, (an ancillary action), and unload theroller. Either type of finishing machine is also capable of tucking inexcess fabric on one end of the roller to increase the surface area ofthe roller that can be exposed to paint, or for aesthetic purposes.

As an alternative to or in addition to using a finishing machine, rollerfabric can be pre-finished by cleaning, shearing, vacuuming, de-linting,or otherwise manipulating it inline before it is wound around a mandrelor otherwise applied to a core as a part of any paint rollermanufacturing process. The fabric can be treated either before it isapplied to a core, or even after the fabric has been applied to thecore, and before the roller cores are cut to desired lengths. Finishingprocesses other than beveling and spinning can be performed prior toroller cores being cut to desired lengths.

In an embodiment, roller cores are marked with a day/date code or otheridentifying codes/marks on the inside portion of the core. In anembodiment, marking can be accomplished by laser marking strip material117, 119 (composed of any material) before it is wound around themandrel, or by laser marking the core of any tube after rollers are cutto length. The printing/laser marking/burning of the code can also takeplace during the finishing process, potentially as a separate station ofthe process, or this function can be incorporated into a finishingstation of the finishing machine 147.

In an embodiment, a method for manufacturing paint rollers includeswinding an inner strip of material and an outer strip of material abouta mandrel in offset relation, the inner strip of material and the outerstrip of material each comprising polypropylene or polypropylene and atleast one filler in proportions of polypropylene to filler that resultin final paint roller shrinkage of less than 0.015 inches per inch offinal paint roller length or less than 0.87 percent of the final paintroller length. An adhesive is applied to at least a portion of the outerstrip as it is wound about the mandrel. A length of fabric is woundabout at least the outer strip to form a paint roller tube, andcompression is applied to the paint roller tube. A precision measuringor sensing device is used to control a cutting device so as to cut thepaint roller tube into final paint roller lengths online with the paintroller tube manufacturing process and prior to the paint roller tubebeing allowed to harden and set. In an embodiment, the proportions ofpolypropylene to filler may result in final paint roller shrinkage ofless than 0.010 inches per inch of final paint roller length, less than0.006 inches per inch of final paint roller length, or less than 0.004inches per inch of final paint roller length.

The methods and system are described above in the context of a two-stripprocess for manufacturing paint rollers. One skilled in the art willrecognize that the same or similar methods can be used in a single-stripprocess, a three-strip process, or the like, without departing from thespirit and scope of the invention.

It is within the scope and spirit of the inventions described hereinthat a continuous process of manufacturing paint rollers employs acutter to cut the in-process semi-finished continuous tube of paintroller material prior to setting. It is also within the scope and spiritof the inventions described herein that the length of material that iscut from the continuous tube of paint roller material includes thelength of the desired finished paint roller plus a predetermined amountor range of shrinkage which will permit the cut length to harden and setto a finished length within a manufacturing tolerance. In an embodiment,the predetermined amount of shrinkage may be determined empirically, byoperating the process over a known cut size, or a range of cut sizes andmeasuring the cutting results after they have hardened and set tosubstantially their final size. In an embodiment, the predeterminedamount of shrinkage may be determined through calculation from knownshrinkage properties of each of the relevant constituent materials.Despite the hundreds of millions of thermoplastic paint rollers madeeach year for at least the last twenty years or more, no known paintrollers have been continuously manufactured to finished length solely bycutting the continuously manufactured paint roller tube to aprespecified larger size, and allowing the cut section to harden andset, and thereby shrink. Regardless of the method of determining thepredetermined amount of shrinkage, using an enlarged cut size toaccommodate the predetermined shrinkage has heretofore not been taughtor suggested.

FIG. 2 shows a single-strip embodiment 201 of the two-strip machine andprocess shown in FIG. 1. This embodiment generally operates as per thedescriptions of FIG. 1 above, except that a single strip 117 is usedinstead of the dual strips 117 and 119.

With respect to the process controller 138, the selection interface 141,and the precision measuring device 133 shown in FIGS. 1 and 2 anddiscussed above, it is noted that roller lengths can also be measuredvia a device that uses a mechanical switch that is triggered by theforward motion of the roller tube, or the presence of the roller tube.The mechanical switch, or any other apparatus that is used to measurethe presence of the roller, can be positioned at arbitrary or presetlengths in order to allow operators to quickly change the desired lengthof the roller tube between preset desired lengths. Markers, mechanicalstops, and/or other physical or virtual demarcation devices can beplaced inline with respect to roller tube travel, or parallel orperpendicular to the direction of roller tube travel. Physical/virtualpreset length stops or other demarcations can be used in conjunctionwith or in lieu of a selection device and/or a processor controller. Anembodiment of such method and system is illustrated in FIG. 3.

FIG. 3 shows a paint roller tube 127 traveling through a machine past aseries of preset notches 301, 302, 303, 304 into which one or moresensors 133 is inserted. The preset notches 301, 302, 303, 304correspond to different paint roller lengths, e.g., three inch, sixinch, nine inch and 12 inch. In an embodiment the sensor 133 is a“flipper” switch is triggered whenever the roller tube is pushed againstit via forward motion. The switch 133 can be positioned at preset orarbitrary intervals that allow the operator to quickly change theswitch's position between desired lengths. In this manner, thetriggering/sensing device that is utilized can be positioned preciselywhere the manufacturer desires to position it. Instead of using aswitch, an optoelectronic array, Hall effect device, or other suitablesensor or measuring device could be used.

In addition to embodiments wherein a trigger is moved, other embodimentscan utilize radar or other non-contact measuring devices to measure alength of roller tube as it passes by the scanning area of themanufacturing system. The length can be continually assessed, and oncethe device decides that the length is adequate as per operatorinstructions, the device then sends a signal to cut. All devices caneither communicate with an intermediary process controller, or directlywith the cutting device itself.

Advantages of the present invention over the present inventor's priorpatents include, but are not limited to the following. It should benoted that some but not all embodiments of the present invention provideeach of these advantages. The present invention can provide asingle-step in-line process for manufacturing a paint roller usinginline cutting, rather than a two-step offline process, thereby reducingthe amount of time, resources, labor, machinery, and waste materialsrequired to produce paint rollers in final lengths. Machines operatingaccording to the present invention can be configured to use lessexpensive molten material that includes one or more fillers. In additionto not requiring additional labor, space, and time to deal with rollertubes as opposed to rollers cut to desired final lengths, other benefitsinclude:

-   -   If roller tubes are constructed of materials that reduce roller        tube shrinkage relative to materials that experience greater        shrinkage (as described above), waste is reduced, and thus, less        material is required to make each paint roller. Historically, 65        inch tubes were produced because up to one inch of shrinkage was        expected, and because one inch of material was needed to        accomodate imprecision in the cutting process. Although using a        compounded polypropylene material reduced shrinkage, it did not        reduce waste because manufacturers have continued to manufacture        paint rollers by producing 65″ sticks. Indeed, persons of        ordinary skill in the art failed to recognize the benefits of        the present invention, which may dramatically reduce waste.    -   Eliminating the need for recutting—that is, to cut rollers to        desired lengths from sticks—saves both capital and labor costs        associated with owning and operating the equipment needed to cut        sticks into paint rollers of exact lengths. Eliminating the need        for recutting also saves the cost of storage space that was        taken up by intermediary storage of roller tubes and the        recutting equipment.    -   Overall manufacturing time decreases with the elimination of        recutting paint roller tubes.

It is noted that the last two benefits accrue to anyone that uses inlinepaint roller cutting with any paint roller manufacturing process,including spiral-winding processes using any strip and resin material,and any non-spiral-winding processes. With respect to non-spiral windingprocesses, the methods and systems described herein can be used forinline cutting with processes such as those that use extruded tubes.Extruded tubes can be pre-fabricated before the paint rollermanufacturing process or extruded as part of the paint rollermanufacturing process. This includes extruded tubes that rotate as theyare made inline.

Reference in this specification to “an embodiment” or “the embodiment”means that a particular feature, structure, or characteristic describedin connection with the embodiment is included in at least an embodimentof the disclosure. The appearances of the phrase “in an embodiment” invarious places in the specification are not necessarily all referring tothe same embodiment, nor are separate or alternative embodimentsmutually exclusive of other embodiments. Moreover, various features aredescribed which may be exhibited by some embodiments and not by others.Similarly, various requirements are described which may be requirementsfor some embodiments but not other embodiments.

As used herein, and especially within the claims, ordinal terms such asfirst and second are not intended, in and of themselves, to implysequence, time or uniqueness, but rather are used to distinguish oneclaimed construct from another. In some uses where the context dictates,these terms may imply that the first and second are unique. For example,where an event occurs at a first time, and another event occurs at asecond time, there is no intended implication that the first time occursbefore the second time. However, where the further limitation that thesecond time is after the first time is presented in the claim, thecontext would require reading the first time and the second time to beunique times. Similarly, where the context so dictates or permits,ordinal terms are intended to be broadly construed so that the twoidentified claim constructs can be of the same characteristic or ofdifferent characteristic.

The above embodiments and preferences are illustrative of the presentinvention. It is neither necessary, nor intended for this patent tooutline or define every possible combination or embodiment. The inventorhas disclosed sufficient information to permit one skilled in the art topractice at least one embodiment of the invention. The above descriptionand drawings are merely illustrative of the present invention and thatchanges in components, structure and procedure are possible withoutdeparting from the scope of the present invention as defined in thefollowing claims. For example, elements and/or steps described aboveand/or in the following claims in a particular order may be practiced ina different order without departing from the invention. Thus, while theinvention has been particularly shown and described with reference toembodiments thereof, it will be understood by those skilled in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the invention.

What is claimed is:
 1. A method for manufacturing paint rollers,comprising: winding an inner strip of material and an outer strip ofmaterial about a mandrel in offset relation, the inner strip of materialand the outer strip of material each comprising material that results ina final paint roller which shrinks axially by less than 2.5 percent ofthe final paint roller axial length upon hardening and setting; applyingan adhesive to at least a portion of the outer strip as it is woundabout the mandrel; winding a length of fabric about at least the outerstrip to form a paint roller tube; applying compression to the paintroller tube while advancing the paint roller tube in a directionparallel to the mandrel; using a precision measuring or sensing deviceto control a cutting device causing the cutting device to cut theadvancing paint roller tube into pre-selected lengths prior to the paintroller tube hardening and setting; and, allowing the cut lengths ofpaint roller tube to harden and set into final paint roller lengths. 2.The method for manufacturing paint rollers according to claim 1, furthercomprising a step of changing the pre-selected lengths from one of aplurality of preset lengths to another of the plurality of presetlengths by operating a device in operative communication with thecutting device or the precision device.
 3. The method for manufacturingpaint rollers according to claim 2, wherein the plurality of presetlengths comprises at least two of: three inches, four inches, four and ahalf inches, six inches, six and a half inches, seven inches, nineinches, twelve inches, fifteen inches, and eighteen inches.
 4. Themethod for manufacturing paint rollers according to claim 1, wherein theadhesive comprises polypropylene and filler in proportions ofpolypropylene to filler that result in final paint roller shrinkagewhich varies by less than 0.1 percent per final paint roller axiallength.
 5. The method for manufacturing paint rollers according to claim1, wherein the adhesive comprises polypropylene and filler inproportions of polypropylene to filler that result in final paint rollershrinkage of less than 0.05 percent per final paint roller axial length.6. The method for manufacturing paint rollers according to claim 1,wherein the adhesive comprises a combination of calcium carbonate andblend of polypropylene, the combination having an effective MFR withinthe range of 80-170 g/10 min.
 7. The method for manufacturing paintrollers according to claim 1, wherein the inner strip of material andthe outer strip of material comprise a combination of calcium carbonateand polypropylene, with calcium carbonate ranges from 10-70% CaCO3 byweight.
 8. The method for manufacturing paint rollers according to claim1, wherein the step of cutting the paint roller tube into pre-selectedlengths comprises using a rotary cutter.
 9. The method for manufacturingpaint rollers according to claim 1, wherein the step of cutting thepaint roller tube into pre-selected lengths comprises using a travellingsaw or stationary saw.
 10. The method for manufacturing paint rollersaccording to claim 1, wherein the inner strip and the outer strip eachcomprise at least 10 percent and not more than 70 percent filler byweight.
 11. The method for manufacturing paint rollers according toclaim 10, wherein the filler comprises calcium carbonate.
 12. The methodfor manufacturing paint rollers according to claim 1, wherein the finalpaint roller length measured axially is three inches, four inches, fourand a half inches, six inches, six and a half inches, seven inches, nineinches, twelve inches, fifteen inches, or eighteen inches.
 13. Themethod for manufacturing paint rollers according to claim 1, wherein thestep of using the precision device to control the cutting device resultsin cutting the paint roller tube into desired axial lengths with atolerance lower than +/−0.01 inches per final paint roller length. 14.The method for manufacturing paint rollers according to claim 1, whereinthe step of using the precision device to control the cutting deviceresults in cutting the paint roller tube into desired axial lengthsonline with a tolerance lower than +/−0.005 inches.
 15. The method formanufacturing paint rollers according to claim 1, wherein the step ofusing the precision device to control the cutting device results incutting the paint roller tube into desired axial lengths online with atolerance of +/−0.0025 inches.
 16. The method for manufacturing paintrollers according to claim 1, wherein the step of using the precisiondevice to control the cutting device is performed when an exteriorsurface of the tube has a temperature that is more than 90 degreesFahrenheit.
 17. The method for manufacturing paint rollers according toclaim 1, wherein the step of winding a length of fabric about at leastthe outer strip comprises winding a length of coated fabric about atleast the outer strip.
 18. A single-strip method for manufacturing paintrollers, comprising: winding a strip of material about a mandrel, thestrip of material comprising polypropylene and at least one filler inproportions of polypropylene to filler that result in final paint rollershrinkage which varies by less than 0.1 percent of the final paintroller axial length; applying an adhesive to at least a portion of thestrip as it is wound about the mandrel; winding a length of fabric aboutat least a portion of the strip to form a paint roller tube; applyingcompression to the paint roller tube; using a precision device tocontrol a cutting device so as to cut the paint roller tube intopredetermined lengths prior to the paint roller tube hardening andsetting; and, allowing the cut lengths of paint rollers tube to hardenand set into final paint roller lengths.
 19. A method for manufacturingfinished-length thermoplastic paint rollers from a continuouslymanufactured tube of paint roller material having an exteriortemperature in excess of 90 degrees Fahrenheit, comprising:predetermining an amount of shrinkage that will occur on a cut sectionof a continuously manufactured tube of paint roller material; cutting asection of the continuously manufactured tube of paint roller materialin an axial length equal to a desired finished-length thermoplasticpaint roller plus the predetermined amount of shrinkage; and allowingthe cut section to harden and set to the desired finished-lengththermoplastic paint roller.
 20. The method for manufacturingfinished-length thermoplastic paint rollers according to claim 1,further comprising a step de-linting the cut section.